/Engine/Source/Runtime/GeometryCore/Public/GeometryTypes.h
TIndexMapstores mappings between indices, which are assumed to be an integer type. Both forward and backward mapping are stored
template<typename IntType> struct TIndexMap
bool
bWantForward
bool
bWantReverse
TMap< IntType, ...
ForwardMap
TMap< IntType, ...
ReverseMap